Members of the Occupy Wall Street movement are arrested by NYPD officers after protesting at Zuccotti Park in New York March 17, 2012. Photo: Reuters

On Saturday night, New York City police arrested dozens of Occupy Wall Street protesters in and around Lower Manhattan's Zuccotti Park. Hundreds had gathered there to mark the six-month anniversary of the first Occupy Wall Street rally.

The day began with gatherings and marches, reports the New York Times. Protesters took to the streets of the Financial District, carrying signs condemning corporate greed and chanting, We are the 99 percent!

Around 2 p.m., police began corralling the protesters and making arrests. Witnesses reported officers forcibly dragging people away and pushing a line of protesters up against a wall.

By nightfall, the protesters had reassembled at Zuccotti Park, their former base of operations. At 11:30 p.m., a police commander announced that the park was closed. When protesters shouted that the space should remain open, the commander said that all those who remained would be placed under arrest.

NYPD Detective Brian Sessa told AP the situation was calm until Brookfield Properties, which owns Zuccotti Park, sent in security to convince occupants to vacate. When that didn't work, Brookfield asked city police to step in.

Sessa said the protesters were breaking rules by bringing tents and sleeping bags. He also asserted that electrical boxes may have been tampered with.

Protesters dispute that version of events. Occupier Sandra Nurse told AP that there were no sleeping bags or tents in the park. There was a banner hung between two trees and a tarp thrown over it ... It wasn't a tent, she said. It was an erect thing, if that's what you want to call it.

Police swept the park around midnight, using plastic handcuffs to arrest dozens of protesters.

A blog associated with the movement posted reports of police engaging in unnecessarily violent behavior, including smashing a protester's head against a window.

Occupy Wall Street has operated largely under the radar since protesters were evicted from Zuccotti Park in mid-November, but organizers have been holding meetings and events all winter in preparation for a springtime resurgence, according to the blog.

The movement has many more events planned throughout March and April. Organizers are also trying to spark a large national protest on May 1.